Sudden loss of oil pressure - Ideas?

[beachbuggy61]

Hi all,

Took my new engine out for a run and all was going well for about 10 minutes, when it suddenly lost oil pressure!

Bit of background:

Oil level on the dipstick is A-OK
No blown lines. Not even a drip of oil externally visible anywhere. Even the rocker covers are dry!!
Have oil pressure gauge and oil light. Both the light came on and the oil pressure gauge showed a drop to zero so I'm figuring the pressure switch and the gauge sensor are confirming that each other is working.

Engine is a brand newly built 2332cc. Had some problems getting oil pressure when I first cranked her over. Figured maybe I'd put something together wrong with the oil pump. Took the cover off, turned the engine by hand, and the gears were moving fine (new oil pump). Checked the pick up extension was on ok (I've got a small pot extension under the sump) and all ok. Made sure external filter and lines were full of oil. Put it all back together and eventually got oil pressure. Has been fine since. Ran the engine at 2500rpm to bed the cam in, changed the oil and filter - all good and pressure again as soon as I fired it.

I'm at a loss to think what has happened. Before I pull the oil pump apart again to see if maybe the pump drive has sheared off, I thought I'd ask if anyone has any ideas...
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"The Lord does not subtract from the life of a man, the hours spent on his Volkswagen" Anon.

[Quokka42]

Are you saying you have checked the pickup extension again?
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[beachbuggy61]

No, I haven't checked it again today, but I also figure that if it's reading full (well, slightly above) on the dipstick, there should be enough oil in there to pick up even if the extension had come off and it was only picking up from the standard pick up.

You think differently? Should that be the first thing I check again?
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"The Lord does not subtract from the life of a man, the hours spent on his Volkswagen" Anon.

[Quokka42]

Sometimes the actual pickup comes loose from the case, which you would tend to notice when checking the extension. If you have a mini sump I wouldn't expect no oil pressure at all without the extension.
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[theDrew]

if you pull the OP switch, and turn it over, do you see oil coming out there?
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[Cusser]

You don't have an earlier oil pump in an engine with a dished camshaft, do you? The oil pump gear is longer for the dished-cam engines.
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[beachbuggy61]

Thanks Quokka, that's what I figured too. The wierd thing is that it just dropped suddenly to zero, I'd expect some pressure too. Even If it had dropped a bearing suddnely there would be something there...

Good thought Drew, I'll try that before I start pulling things apart.

Cusser, I don't think I have an earlier pump.... If I did have an earlier one with a dished camshaft, then wouldn't it have always had no pressure? Or would this combo mean that sometimes the pump drive would engage and sometimes not...?
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"The Lord does not subtract from the life of a man, the hours spent on his Volkswagen" Anon.

[66brm]

Another thing to check on is your oil control plungers, if one gets jammed down you could be venting straight back to sump
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[beachbuggy61]

Ok, progress so far.

Checked plungers and they're all freely moving.

The engine has a full flow set-up. I pulled the cover off the oil pump and the gears are turning ok so given that it's a brand new pump and was working fine, I'm thinking that the pump should be ok. The gears look ok.

The outlet on the front of the pump goes to a remote filter so I took the hose off the filter and cranked the engine and nothing comes out of the hose.

My thinking is that the pick-up pipe has come away inside the case. Since it suddenly lost pressure I'm thinking something broke and that's the only thing I can think of.

Any other ideas before I remove the engine and split the case to have a look??

Thanks in advance...
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"The Lord does not subtract from the life of a man, the hours spent on his Volkswagen" Anon.

[esde]

Drop the sump plate, you can then grab the end of the pickup tube and give it a wiggle. If it's out of the case you'll know. It would be hard for it to fall out with the end secured under the sump stud, but I see that nut missing a lot.
You mentioned that the pump gears turn fine. In fact, they should not turn without the engine as one is keyed into the camshaft. Did you pull the gears, and was the flat drive intact? I've not experienced it, but have seen pictures of the drive broken off.

[beachbuggy61]

Thanks esde I'll check the end of the pick up tube.

When I say the gears turned fine, it was when I turned the engine over by hand. I checked the end of the pump drive that goes into the cam slot and it is in perfect condition. You can see a slight mark on it where it has been engaging the cam so I'm confident the cam is turning it properly.

I've never experienced the pick-up tube coming out of the case but it's the only explanation I can think of...
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"The Lord does not subtract from the life of a man, the hours spent on his Volkswagen" Anon.